Selection of receive-queue based on packet attributes

ABSTRACT

According to embodiments of the invention, there is provided a method for operating a network processor. The network processor receiving a first data packet in a stream of data packets and a set of receive-queues adapted to store receive data packets. The network processor processing the first data packet by reading a flow identification in the first data packet; determining a quality of service for the first data packet; mapping the flow identification and the quality of service into an index for selecting a first receive-queue for routing the first data packet; and utilizing the index to route the first data packet to the first receive-queue.

CROSS-REFERENCE TO RELATED APPLICATIONS

This invention claims priority to the foreign application EP10306438.2filed Dec. 16, 2010 in the European Patent office.

BACKGROUND

1. Field

The invention relates generally to a method for operating a networkprocessor. In particular. the invention relates to a method forselecting a receive-queue for a packet out of a stream of data packets.The invention relates further to a network processor and a systemadapted for a programmable selection of receive-queue based on multipleattributes found in a packet.

2. General Background

Today's computing environments, in particular those of large datacenters like cloud computing data centers, require a high level ofswitching capacities for connecting a large number of server computerswith each other. The proliferation of standard servers and the growingusage of virtualization technology increase this need even more.

With the advent of virtualization of network adapters, and the newrequirement for deep packet, inspection, a more complete and flexibleselection of receive-queues is needed. On one hand, virtualizationimplies that a receive-queue must be selected in a pool of queues,belonging to a given logical port. On the other hand, deep packetprocessing calls for a queue selection dependent on informationpotentially extracted anywhere in the packet including the payload ofthe data packet.

Therefore. there is a need for a dynamic, flexible, configurable andre-configurable method to handle the selection of receive-queues innetwork processors.

SUMMARY

According to embodiments of the invention, there is provided a methodfor operating a network processor. The network processor receiving afirst data packet in a stream of data packets and a set ofreceive-queues adapted to store receive data packets. The networkprocessor processing the first data packet by reading a flowidentification in the first data packet: determining a quality ofservice for the first data packet; mapping the flow identification andthe quality of service into an index for selecting a first receive-queuefor routing the first data packet; and utilizing the index to route thefirst data packet to the first receive-queue.

DRAWINGS

The above-mentioned features of the present invention may be betterunderstood, and its numerous objects, features, and advantages madeapparent to those skilled in the art by taken in conjunction with theaccompanying drawings wherein like reference numerals denote likeelements and in which embodiments the invention are described, by way ofexample only, and with reference to the following drawings:

FIG. 1 shows a block diagram of an embodiment of the invention describedherein.

FIG. 2 illustrates a block diagram of an embodiment of the invention ina network processor.

FIG. 3 illustrates a more detailed block diagram of an embodiment in anetwork processor.

FIG. 4 shows a block diagram illustrating an embodiment of building anindex for receive-queues.

FIG. 5 illustrates a block diagram of an overview on the inventiondescribed herein in a network processor.

FIG. 6 illustrates a block diagram of an embodiment of the inventiondescribed herein as a network processor as part of an end-point device.

FIG. 7 shows a more detailed. flow chart of an embodiment of theinvention described herein.

DETAILED DESCRIPTION

Embodiments of the invention arc described below with reference todrawings in detail.

It is noted that the received data packets comply with a networkstandard. e.g., the protocol (internet protocol) and more particularlyIPv4 or IPv6. However, the invention described herein is also applicableto other network protocols based on data packets. The hashing of a flowidentification (id) from a data packet is performed by pica-code or byhardware. The network processor may be built as a single integratedchip.

In the context of this application and the embodiments of the inventiondescribed herein the following principle terms have been used:

Network processor—The term network processor denotes a special purposeprocessor required for high-speed and high-throughput networks. It maybe in, for example, a router, a switch, an intrusion detection device, asession border controller, a network monitoring system and the like, oralso in an end point network device, such as an intranet appliance in acloud computing environment. The network processor has specificfunctionality in order to respond and react to incoming as well asoutbound network traffic. Network processors may have comparablecomputing units, e.g., a as a general purpose or controlling processor.On the other hand, network processors may have dedicated units forpattern matching for an identification of specific patterns in datastreams. Network processors may also have functions that may beimplemented using software elements. In contrast to general purposeprocessors, the controlling software elements inside the networkprocessors may be pico-code.

Data packet—The term data packet denotes a sequence of e.g., bytes in adata stream. A protocol like TCP/IP (transmission controlprotocol/internet protocol) may be based on data packets of a certainlength having defined positions within the data packet for specificcodes.

Receive-queue—The term receive-queue denotes a storage area dedicatedfor storing incoming data packets or bytes or series of bytes of data,i.e., data words. A receiving device, e.g., a network processor. mayhave several receive-queues to differentiate data packets with differentpriorities. High priority data packets may be stored in ahigh-priority-receive-queue before it may be further processed, e.g.,retransmitted, analyzed. etc. A typical mode of operation may be inprocessing data in a high-priority-receive-queue as long as data is insuch a queue. Only if the high-priority-receive-queue is empty, datapackets of other, lower priority-receive-queues may be furtherprocessed.

Hashing, Hash Function, Hash Code—The term hashing denotes a usage of ahash function. A hash function is any well-defined procedure ormathematical function that converts a large, possibly variable-sizedamount of data into a small datum, usually a single integer that servesas an index to an array. The values returned by a hash function arecalled hash values, hash codes, hash sums, checksums or simply hashes.Hash codes are often used to speed-up table lookup tasks. A hasherdenotes a hashing function that may be implemented in hardware orsoftware.

Quality of service—This term denotes a specific code as part of a datapacket specifying a need for a high priority for further processing.This may often be the case for streaming video or streaming audio dataor IP telephony in order to ensure that there be no break orinterruptions in the stream of video or audio data. In an IP packet theterm TOS (type of service) may be used instead of QoS. A TOS code may bepart of an IP-header section.

Classification criterion function—This term denotes a function used fora classification of data packets supporting the process of selecting aproper receive-queue for a data packet. There may be a plurality ofcriteria functions beside a quality of service classification function.These additional classification criteria functions may, for example, bebased on a hardware accelerator that hashes a flow-id received from aparser, a ternary CAM that performs a look-up of any key assembled bythe parser to identify a flow-id, or a direct queue address delivered bythe parser. In this case, specific registers may be used that areavailable to the parser for providing an offset or an index under amicrocode/pico-code control.

Combination of classification criteria functions—This term denotes thatseveral criteria functions are available and are—in a combined way—usedfor selecting a receive-queue. A QoS specification can be handledseparately.

TCAM—The term TCAM (ternary content addressable memory) denotes aternary content addressable memory. A CAM (content addressable memory)is a special type of computer memory used in certain high-speedsearching applications. It may also be known as associative memory,associative storage, or associative array. A binary CAM is the simplesttype of CAM which uses data search words consisting entirely of 1s and0s. Ternary CAM (TCAM) allows a third matching state of “X” or “Don'tCare” for one or more bits in the stored data word, thus addingflexibility to a search process.

Physical port—The term physical port denotes a physical connection forincoming data. A plurality of ports may be provided. Each physical portmay be able to handle a plurality of virtual or logical ports.

Logical port—The term logical port denotes a virtual port belonging to aphysical port. Each physical port may be able to handle a plurality of alogical port(s). Each incoming data packet is associated to a partitionor logical port. If, e.g., four physical ports are implemented and fourlogical ports are implemented, a total number of 16 logical ports arehandled.

Logical port configuration table—This term denotes a translationmechanism to translate data received from a parser into an index basefor a receive queue address, an offset for QoS data specifying how manybit to be used from a QoS signal as well as specifying which and howadditional bit from classification criteria function are used.

Typical networks, like e.g., those being based on the TCP/IP protocol,transmit information over networks based on data packets. Streams ofdata packets arc sent from one device or server over linking devices,like e.g., switches and/or routers, to other devices or servers. Thedevices include any network attached device including servers, PCs,storage area network systems, printers, scanners, dedicated networkequipment, or any other network attachable device. The network may be awired network, a wireless network or a mix of both.

In a typical embodiment of the invention described herein, incomingpackets are parsed by a parser, depending on information found duringthe parsing process, and directed to dedicated receive-queues. Thedirection into different receive-queues is based on several criteria.E.g., packets with a high priority, e.g., those for a voice-over-IPlink, are directed into a high priority receive-queue for a fast,further processing. Packets that are not time critical arc directed to alow priority receive-queue, etc.

A selection of a receive-queue is based on a combination of a flowidentifier and a quality-of-service parameter found in data packetheaders.

Several approaches arc described to handle priorities of data packetsand a receive-queue selection.

In one embodiment, a method for operating a network processor isprovided. The method comprises receiving a stream of data Packets andproviding receive-queues, adapted to store received data packets.Furthermore, the method comprises selecting a receive-queue out of theset of receive-queues for a data packet. The selecting is based on acombination of classification functions and a quality-of-servicefunction. One of the classification functions comprises a hashing of aflow identification, wherein the flow identification is in the receiveddata packet.

In particular, the hashing function may be performed by a hasherutilized for other purposes anyway. Thus, an existing hash function maydynamically be repurposed for selecting a receive-queue. Althoughdedicated to a special task a network processor may also be seen asbeing similar to a general purpose processor in the sense of executingsoftware instructions.

According to another embodiment a network processor is provided. Thenetwork processor comprises a receiving unit adapted for receiving astream of data packets. Moreover the network processor comprisesreceive-queues adapted to store received data packets. Additionally, thenetwork processor comprises a selecting unit adapted for selecting areceive-queue out of the receive-queues for a data packet in the set ofdata packets. The selection is based on a combination of classificationfunctions and a quality-of-service function. One of the classificationfunctions comprises a hashing of a flow identification in the receiveddata packet.

The above-described method for operating a network processor offers someadvantages. The separation and combination of different classificationcriteria functions together with a service criterion function allow fora very flexible and elegant way to select a receive-queue. Inparticular, a hashing of a flow-id in the data packet beside a qualityof service criterion improves the flexibility in receive-queueselection.

These advantages are also achieved by the network processor and thesystem adapted for a programmable selection of a receive-queue based onmultiple attributes found in a packet.

According to one embodiment of the method, the classification functionscomprises looking-up a ternary content addressable memory (TCAM) in thereceived data packet. This direct usage of a TCAM match for a pattern ina data packet increases the flexibility of identifying a receive-queueeven more.

In another embodiment of the method, the classification functions uses aqueue identifier received from a parser parsing the stream of datapackets. This direct usage of a queue identifier found by the parser ina data packet increases the flexibility of identifying or selecting areceive-queue.

In another embodiment of the method, the classification functionlooking-up a ternary content addressable memory has a higher prioritythan the classification criteria function hashing of a flowidentification. In the case of a TCAM match, the hash value isoverwritten.

In another embodiment of the method, the classification function using aqueue identifier has a higher priority than the classification functionlooking-up a ternary content addressable memory. If the queue identifieris directly found in the received data packets, it overwrites anyreceive-queue identification data found in a TCAM match.

In another embodiment of the method, the selecting utilizes an indexbase From a logical port configuration table (LPCT), based on a logicalport (LP) identification information received from the parser, forbuilding an index address into a queue table for storing anidentification number or position of the receive-queue. A configurationallowing a base address as well as one or more offsets to the baseaddress for identifying a correct or optimal receive-queue address hasbeen proven to deliver the highest degree of design freedom of a networkprocessor.

This may also be reflected in an embodiment, wherein the classificationfunctions is used to build an offset to the index base.

In another embodiment of the method, a second offset to the base indexis based on the quality-of-service function. Again, such a design ofbase address of a queue and an offset to a base index has been proven toallow very high flexibility in determining receive-queue addresses.

In another embodiment of the method, it is configurable how many bits ofresults of each of the classification criteria functions are used tobuild the index into the queue table. This illustrates the flexibilityof the method. It may be configured, for example, in such a way thatonly the top five bits are used. However, the number of bits used isconfigurable.

In another embodiment of the method, the results of the classificationfunctions are connected to a multiplexer. This solution allows forchoosing the input having a higher priority. If. e.g., there is a TCAMmatch detected, the TCAM result is used instead of a hash functionresult.

In another embodiment, the index into the queue table is based on thebase index and a combined offset built from the quality-of-servicefunction and the classification functions. This combined offset togetherwith the base index—combined with other features mentionedabove—demonstrate again excellent flexibility and configurability foroperating a network processor.

In an embodiment, a network device for connecting a plurality of inputconnections to a plurality of output connections is provided. Thenetwork device comprises the network processor as described above. Thenetwork device may be, e.g., a router, a switch. an intrusion detectiondevice, a session boarder controller, a network monitoring system andthe like or an end point network device, such as an intranet appliancein a cloud computing environment like, e.g., a client or a servercomputer system.

It should be noted that embodiments may take the form of an entirehardware implementation, an entire software embodiment or an embodimentcontaining both, hardware and software elements. in an embodiment, theinvention may be implemented in software which includes, but is notlimited to, firmware, resident software and microcode and/or pico-code.

In one embodiment, a data processing program for execution in a dataprocessing system may he provided comprising software code portions forperforming the method, as described herein, when the program is run on adata processing system. The data processing system may be a computer orcomputer system attached to the asset management system viacommunication means.

Furthermore, embodiments may take the form of a computer programproduct, accessible from a computer-usable or computer-readable mediumproviding program code for use, by or in connection with a computer orany instruction execution system, in particular a network processor. Forthe purpose of this description, a computer-usable or computer-readablemedium may be any apparatus that may contain means for storing,communicating, propagating or transporting the program for use, by or ina connection with the instruction execution system, apparatus, ordevice.

The medium may be an electronic, magnetic, optical, electromagnetic,infrared or a semi-conductor system for a propagation medium. Examplesof a computer-readable medium may include a semi-conductor or solidstate memory, magnetic tape, a removable computer diskette, a randomaccess memory (RAM), a read-only memory (ROM), a rigid magnetic disk andan optical disk. Current examples of optical disks include compactdisk-read only memory (CD-ROM), compact disk-read/write (CD-R/W), DVDand Blu-Ray-Disk.

It should also be noted that embodiments of the invention have beendescribed with reference to different subject-matters. In particular,some embodiments have been described with reference to method typeclaims; whereas other embodiments have been described with reference toapparatus type claims. However, a person skilled in the art will gatherfrom the above and the following description that, unless otherwisenotified, in addition to any combination of features belonging to onetype of subject-matter, also any combination between features relatingto different subject-matters, in particular between features of themethod type claims, system, computer program product, and features ofthe apparatus type claims, is considered as to be disclosed within thisdocument.

The aspects defined above and further aspects of the present inventionare apparent from the examples of embodiments to be describedhereinafter and are explained with reference to the examples ofembodiments, but to which the invention is not limited.

In the following, a detailed description of the figures are given. Allillustrations in the figures are schematic.

FIG. 1 illustrates a method 100 for operating a network processor. Themethod 100 comprises receiving, 102, a stream of data packets andproviding, 104, receive-queues adapted to store received data packets.Furthermore, the method comprises selecting, 106, a receive-queue outoldie receive-queues for one oldie data packets. The selecting is basedon a combination of classification functions and a quality-of-servicefunction. One of the classification functions comprises a hashing of aflow identification, wherein the flow identification is in the onereceived data packet.

FIG. 2 illustrates an example network processor 200 for which theinvention described herein may be implemented. Via link 230 data packets201 come in from a network (not shown). A plurality of physical portsare provided, in an example embodiment four ports are provided. Eachphysical port may be adapted to handle a plurality of virtual ports. Inone embodiment, four virtual ports per each physical port is configured.The data ports may be adapted to running in 10 Gigabit networks. Theymay also be functional in one Gigabit and 100 Megabit networks. Theincoming data packets 201 are received via line 230 by a receiving unit204 having at least three components: a register horizontal left (HR)208, a register horizontal right (HL) 206 and a status register 214. Adata packet is received by register horizontal right 208. At the end ofa packet processing, the status register 214 receives data. After thedata is received by register horizontal right 208 they are passed On toregister horizontal left 206. Data packets 201 exit this data path viabus 202 for further processing. All data packets are exposed to theparser 216 via bus 210. Also the status at an end of a data packet isexposed to the parser via bus 212. In one embodiment, a 128bit wide datapath is used. In this case, register 206 and 208 are each 16 byteregisters so that the parser 216 is exposed to a 32-byte sliding windowof packet data.

The block 218 comprises a series of so-called action machines or in moregeneral words hardware accelerators 220, 222, 224, 226, 228. Block 218is in a bidirectional data exchange with the parser 216 via link 230. Itis noted that far more data traffic may flow from the parser to theaccelerators in order to release the parser from specific workloads. Alllinks may he more than one bit wide.

The action machines or hardware accelerators 220, 222, 224, 226, 228support dedicated functions required in the network processors that maybe either repetitive and/or require a high calculation performance. Theparser 216 function as well as the functions of the action machines 220,222, 224, 226, 228 may be based on unit specific pico-code. Althoughbeing pico-code, it is loaded into the processor and thus updated ifrequired. Examples of action machines comprise a hashing action machine,a TCAM action machine, quality of service action machine, dedicatedlifters, markers, etc. The action machines may be dedicated to releasethe parser in regard to specific tasks. In one embodiment, the parser isimplemented as a finite state machine (FSM). A split between the parserand specific action machine enables parallel processing, and thus theability to handle high-speed network traffic.

FIG. 3 illustrates an exemplary embodiment as part of the networkprocessor supporting the method of the invention described herein. Threestages separated by dotted lines 302 are shown: a virtualization stage304, a QoS (quality of service) stage 306 and a classification stage308. Via line 310 logical IDs are received by a logical port conversiontable 312 (LPCT). The LPCT block has three outputs: an index base 314, aQoS select signal 316 and a classification offset select signal 318. TheQoS block 320 receives QoS bits from the parser via line 322. An outputof the QoS block 320 is directed to a multiplexer 326.

The offset select signal 318 is linked to multiplexer 328, whichreceives a flow-id offset signal 330 from a multiplexer 332. Themultiplexer 332 receives input from several action machines: a hasher334, a TCAM action machine 336, and a direct queue address function 338.

The hasher 334 receives an n-tuple from the parser via line 340. TheTCAM action machine 336 receives packet fields from the parser via line342. The direct queue address function 338 receives direct queueaddresses from the parser via line 344. All lines earning to thedifferent stages in FIG. 2 are illustrated in a combined manner byreference numeral 230 of FIG. 2.

An adder 346 adds the queue address offset coming in via line 314, theoffset coming in by line 348 and the offset coming in by line 350 frommultiplexer 328.

The final index into the queue table 358 is selected by the multiplexer352. Either the direct queue table address from the direct queue tableaddress function 338 via line 354 or the index based on the adder 346 isused by line 356. A decision regarding which index is used is based on acontrol bit (not shown) provided by queue table address function 338.The queue table 358 contains queue numbers issued by line 360 Forsubsequent usage.

FIG. 4 illustrates a more detailed view on an embodiment of the combinedeutities involved in the receive-queue selection. Blocks 336, 334, 320represent a TCAM functional block, a hasher, and a QoS functional blockas in FIG. 3, respectively.

Attention is paid to the number of bits used from every function oraction machine for selecting the receive-queue. Block 402 represents aconfiguration function comprising a logical port configuration table 404having seven entries represented by horizontal lines. However, any othernumber of entries is as good as a table with seven entries.

In an embodiment, each horizontal Field of the logical portconfiguration table 404 represents five bits. Thus, busses 406 and 408are each five bits wide. Connection 414 is just one bit wide for a TCAMmatch signal controlling the multiplexer 416. The multiplexer 416selects the signal on line 412 from the TCAM block 336 in ease of a TCAMmatch. Otherwise, the signal on line 410 coming from the hasher 334 isselected. The output of the hasher is typically 32 bit wide, as it maybe required for other purposes within the network processor. However,for this example embodiment only the five most significant bits are usedfor further processing, in particular as input for multiplexer 416.Consequently line 418 also represent a five bit wide signal. This isrepresented by the live shaded boxes 420 composed of lines from a lowerleft side to an upper right side.

Parts of line 408, in particular 3 bits represented by line 422, controlhow many bits are used from signal 418. For this purpose, a masking unit426 is controlled by line 422 which uses 3 bits out of the 5 bit wideline 408. The remaining two bits from line 408 is represented by link424. They are used to specify a masking of 0 to 3 bits by masking unit434 as well as a shift-left of the same number of bits by shift unit432. This means, that an output of masking unit 426, which of five bitswide, is represented by block 428, showing two active bits with stripesto the right. After a shift unit 432 has shifted the bits, an output ofthe shifting unit 432 has the relevant bits on position two and threecounted from the right side. Signal 424 controls mask unit 434 in whicha 3 bit wide output 436 of the QoS function 320 is masked. The stripedboxes 438, showing stripes from top left down to bottom right, indicatesthree priority bits from the QoS function 320. After a masking of theoutput signal from QoS function 320 the number of active bits isreduced, which is illustrated by the example with one active prioritybit as indicated by 440. Both outputs, from shift unit 432—shown asblock 430—and from mask unit 434 are 5 bit wide and are input to anor-gate 442. The output of the or-gate 442 is also 5 bit wide. The adder444 then becomes the base index which comes via line 406 and the offsetas a result of the “or-ing” by gate 442 is fed as a total offset 446 toreceive-queue selection table. Here, the total offset is added to a baseaddress giving the final entry to the receive-queue selection table vialine 448. This table is a 32 by 8 bit register holding pointers to thereceive-queues to be selected.

Block 446 illustrates the final combination of bits in the five bit wideinput field to adder 114. Line 448—five bit wide—carry the signal forselecting the receive-queue.

FIG. 5 shows the network processor 500 comprising a receiving unit 202adapted for receiving a stream of data packets, receive-queues 504—ofwhich two is shown—adapted to store received data packets, and aselecting unit 506 adapted for selecting a receive-queue out of thereceive-queues for one out of the data packets based on a combination ofclassification functions and a quality-of-service function, wherein oneof the classification functions comprises a hashing of a flowidentification comprised in the one received data packet.

Embodiments of the invention may partly be integrated in virtually anytype of computer, regardless of the platform being used suitable forstoring and/or executing program code, in particular micro- orpico-code. For example, as shown in FIG. 6, a computer system 600 mayinclude one or more processor(s) 602 with one or more cores perprocessor, associated memory elements 604, an internal storage device606 (e.g., a hard disk, an optical drive such as a compact disk drive ordigital video disk (DVD) drive, a flash memory stick, etc.), andnumerous other elements and functionalities typical of today's computers(not shown). The memory elements 604 may include a main memory, employedduring actual execution of the program code, and a cache memory, whichprovides temporary storage for at least some program code or data inorder to reduce the number of times, code roust be retrieved fromexternal bulk storage 616 for execution. Elements inside the computer600 are linked together by means of a bus system 618 with correspondingadapters. Additionally, a network processor 600 may be attached to thebus system 618.

The computer system 600 may also include input means, such as a keyboard608, a mouse 610, or a microphone (not shown). Furthermore, the computer600 may include output means, such as a monitor 612 [e.g., a liquidcrystal display (LCD), a plasma display, a light emitting diode display(LED), or a cathode ray rube (CRT) monitor]. The computer system 600 isconnected to a network (e.g., a local area network (LAN), a wide areanetwork (WAN), such as the Internet, or any other similar type ofnetwork, including wireless networks via a network interface connection614 which may also comprise the network processor 500. This allows acoupling to other computer systems. Those, skilled in the art willappreciate that many different types of computer systems exist, and theaforementioned input and output means may take other forms. Generallyspeaking, the computer system 600 includes at least the minimalprocessing, input and/or output means, necessary to practice embodimentsof the invention.

Further, those skilled in the art will appreciate that one or moreelements of the aforementioned computer system 600 may be located at aremote location and connected to the other elements over a network.Further, embodiments of the invention may be implemented on adistributed system having a plurality of nodes, where each portion ofthe invention may be located on a different node within the distributedsystem. In one embodiment of the invention, the node corresponds to acomputer system. Alternatively, the node may correspond to a processorwith associated physical memory. The node may alternatively correspondto a processor with shared memory and/or resources or a smart phone.

Further, software instructions to perform embodiments of the inventionare stored on a computer readable medium, such as a compact disk (CD), adiskette, a tape, or any other computer readable storage device and areloaded to the computer system 600 and also partly to the networkprocessor 500 as pico-code.

FIG. 7 shows a flowchart 700 of how a receive-queue address can hebuilt. References are made to FIG. 4 Which shows device elements forperforming the method.

In step 702 an index base is built by a configuration function. Step 704represents selecting either a TCAM 336 output, in case there has been aTCAM match, or the output of the hasher 334. Only the top five bits (5MSBs) of each output are used in this example embodiment.

In step 706 three bits from the configuration function 402 are used todecide how to mask the result of step 702.

Potentially but not necessarily in parallel, in step 708, a result isbuilt by QoS function 320. The result of this step delivers a three bitresult. In step 710 it is decided—based on two bits from theconfiguration function 402—how many bits of the output of the QoSfunction 320 are masked. The same two bits are used to perform ashifting function on the masked results of step 702.

In step 712 the results of the steps 706 and 708 are combined by alogical or-function. In step 714 the result of the or-function are addedto a base index being delivered by the configuration function. Thisresult is used as an index to a queue table containing receive-queueaddresses, step 716. In a further step 718, the entry of the queue tableis selected and used as an address for the selected receive-queue. Instep 720, the received data packet are stored in the selectedreceive-queue.

It should be noted that several of the steps described regarding theflow chart 700 could be executed in parallel. Executing in parallel is apreferred embodiment, in particular, for the case for executing, theconfiguration function, the hasher function, the TCAM function and theQoS function. If may also apply for the shifting and the masking stepsif the shifting and masking relate to different data flows, e.g., outputof the QoS function and combined output of the TCM and hasher functions,respectively.

While the invention has been described with respect to a limited numberof embodiments, those skilled in the art benefitting from thisdisclosure, will appreciate that other embodiments may be devised, whichdo not depart from the scope of the invention as disclosed herein.Accordingly, the scope of the invention should be limited only by theattached claims.

It should also be noted that the term “comprising” does not excludeother elements or steps and “a” or “an” does not exclude a plurality.Also, elements described in association with different embodiments maybe combined. It should also be noted that reference signs in the claimsshould not be construed as limiting elements.

1-6. (canceled)
 7. A method for operating a network processorcomprising: receiving a first data packet in a stream of data packets;processing the first data packet by reading a flow identification in thefirst data packet; determining a quality of service for the first datapacket; mapping the flow identification and the quality of service intoan index for selecting a first receive-queue in a set of receive-queuesadapted to store receive data packets for routing the first data packet;and utilizing the index to route the first data packet to the firstreceive-queue.
 8. The method of claim 7 further comprising: utilizing ahashing function against the flow identification to construct the index.9. The method of claim 7 further comprising: utilizing a classificationfunction accessing a ternary content addressable memory for the firstdata packet.
 10. The method of claim 7 further comprising: utilizing aquality of service function for identifying the quality of service. 11.The method of claim 7 further comprising: utilizing a parser fordecoding the first data packet; and sending a set of information to aset or other processing units for further processing.
 12. The method ofclaim 11, wherein the set of information further comprising: including alogical port identification and a logical port configuration table.13-18. (canceled)